Chief Justice John Roberts this year said the politics of Senate confirmation hearings give the public the mistaken view that justices are partisan. "We don't work as Democrats or Republicans," he said.
But in interviews last week, Ginsburg made it clear her distaste for the New York businessman.
"I can't imagine what this place would be - I can't imagine what the country would be - with Donald Trump as our president," Ginsburg told the New York Times.
"For the country, it could be four years. For the court, it could be - I don't even want to contemplate that."
She said her late husband would have said: "Now it is time for us to move to New Zealand".
She also told AP that she assumed Democrat Hillary Clinton would win the November election. The 83-year-old Ginsburg was nominated to the court in 1993 by President Bill Clinton.
Asked what would happen if Trump won instead, she said, "I don't want to think about that possibility, but if it should be, then everything is up for grabs."
Her comments were met with a wave of alarm by many judicial ethics experts, who called them surprising if not potentially recusal-worthy should a legal issue involving Trump come before the court.
I think it's a disgrace to the court, and I think she should apologise to the court
But Ginsburg doubled down when she met for a previously scheduled interview with CNN's Joan Biskupic.
"He is a faker," Ginsburg said of Trump. "He has no consistency about him. He says whatever comes into his head at the moment."
She added: "He really has an ego. . . . How has he gotten away with not turning over his tax returns? The press seems to be very gentle with him on that."
Trump got on the line with the New York Times' Maggie Haberman to respond.
"I think it's highly inappropriate that a United States Supreme Court judge gets involved in a political campaign, frankly," Trump said. "I think it's a disgrace to the court, and I think she should apologise to the court. I couldn't believe it when I saw it."
Trump added: "It's so beneath the court for her to be making statements like that. It only energises my base even more. And I would hope that she would get off the court as soon as possible."
Supreme Court spokeswoman Kathleen Arberg said Ginsburg had no comment on Trump's reaction to her comments.
Nominations to the court, Ginsburg has indicated, are at the heart of her concern. There already is one vacancy, and Senate Republicans have refused to hold a hearing on Judge Merrick Garland, President Barack Obama's nominee to take the place of Justice Antonin Scalia, who died in February.
Ginsburg has noted that she and two others on the court will be 78 or older on Inauguration Day 2017.